Salivary IL-6 and hs-CRP levels in Periodontitis Patients with and Without Type 2 Diabetes Mellitus: A Cross-sectional Study

Introduction: The bidirectional relationship between periodontitis and Type 2 Diabetes Mellitus (T2DM) is mediated by inflammatory mechanisms. While both conditions are characterised by systemic inflammation, the relative inflammatory burden in patients with both conditions versus periodontitis alone remains unclear. Salivary biomarkers offer a non invasive method to assess local and systemic inflammation. The present study was done to explore if diabetic patients with periodontitis had a higher inflammatory burden than systemically healthy patients with periodontitis. Aim: To compare salivary levels of Interleukin-6 (IL-6) and high-sensitivity C-Reactive Protein (hs-CRP) between patients, with periodontitis alone and those with both periodontitis and T2DM. Materials and Methods: The present cross-sectional study was carried out in the Department of Periodontics at Pushpagiri College of Dental Sciences, Thiruvalla, Kerala, India, over a period of five months from January to May 2024. The present study enrolled periodontitis patients with and without T2DM. A total of 40 patients were recruited, 20 with periodontitis (P group) and 20 with both periodontitis and T2DM (DM+P group). Clinical periodontal parameters were recorded, and unstimulated saliva samples were collected. Salivary IL-6 was measured using Enzyme-Linked Immunosorbent Assay (ELISA) and hs-CRP using nephelometry. Groups were compared using the Mann-Whitney U test with significance set at p<0.05. Results: The P group showed higher gingival inflammation and percentage of sites with Pocket Depth (PD) >5 mm, while the DM+P group exhibited greater Clinical Attachment Loss (CAL). Mean salivary IL-6 levels were higher in the P group (528.21±492.59 pg/mL) compared to the DM+P group (306.22±307.97 pg/mL; p=0.056). Similarly, hs-CRP levels were higher in the P group (1.0±1.19 mg/L) versus the DM+P group (0.74±0.74 mg/L), though not statistically significant. Conclusion: There were no significant differences in salivary levels of IL-6 and hs-CRP in periodontitis patients with and without Diabetes Mellitus (DM). Interestingly, patients with periodontitis alone demonstrated higher levels of inflammatory markers than those with concomitant diabetes, though differences were not statistically significant. These findings suggest that salivary levels of IL-6 and hs-CRP more reflective of local periodontal inflammation than the systemic diabetic status.